Background/Objective: There is evidence for an antidepressant effect of repetitive transcranial magnetic stimulation (rTMS) but little is known about posttreatment course. Therefore we conducted a placebo-controlled double-blind study in depressed patients in order to investigate the effect of rTMS on depression over 12 weeks after completion of the 2-week stimulation period.

Method: 55 patients with a moderate or severe DSM-IV major depressive episode were randomly assigned to rTMS or sham treatment. rTMS was given daily for 10 days over the left dorsolateral prefrontal cortex with the following treatment parameters: 20 Hz 20 trains of 2 seconds 30 seconds between trains and 80% motor threshold. The effect of rTMS on depression was rated repeatedly with the 17-item Hamilton Rating Scale for Depression (HAM-D) during the 2-week period of stimulation and the 12-week follow-up period conducted from 1997 to 2001.

Results: We found a modest clinically nonrelevant decrease in HAM-D scores in both rTMS and sham patients over 2 weeks of treatment. However over the subsequent 12-week follow-up the rTMS group continued to improve significantly compared with the placebo group.

Conclusion: Decrease of depressive symptoms may continue after the cessation of rTMS stimulation.